Rust-resisting steel and method of producing same



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No Drawing.

To aZZ whom it may concern:

Be it known that 1, Jules H. GRAVELL a citizen of the United States,residing at llllkills Park, in the county of Montgomery and State ofPennsylvania, have invented a new and useful lm rovement inRust-Resisting Steel and Methods of Producing Same, of which thefollowing is a specification.

This invention relates to iron and steel and it is particularly directedto rust resisting steel.

The object of the invention is to provide rolled steel that rusts withdilliculty or is not so liable to rust as ordinary rolled steel found onthe market at the present time.

According to the present methods of making rolled steel and iron, thesteel billet is heated to a high temperature and rolled to the desiredshape. This produces the hot rolled steel of commerce which is coveredwith a substantial coating of oxide which causes it to look black. lit ametallic or bri ht finish is required, the hot rolled steel is pickledwith an acid to remove the oxide and then rolled or drawn cold to securethe high finish. The term rolling will be used to include drawing. Hathin plate or strip is required, it may be processed several times. isannealed during which great care is exer cised to prevent the air fromcontacting with 'the metal while it is heated, as otherwise it would beoxidized and would have to be again pickled to remove the oxide orscale.

Steel produced by these methods rusts rapidly while stored or beingshipped. lit is natural for the metal to rust in the atmosphere, but thenatural rusting is accelerated by the presence of impurities received inthe pickling operation, such for instance as sulphurlc and other acidsand salts.

l have discovered that it a thin coating of iron phosphate is given tothe metal hetore rolling and that if this coating is rolled onto or intothe surface in the rolling eration, the rust accelerators are neutraized and the natural rusting tendencies of the metal are greatlyreduced. Metals treated according to my process are distinguished fromother metals by a darker looking surface and by their freedom fromrusting, and they may be shipped or stored for long periods withoutdanger of rusting although Between the cold rollings the metalRTUhT-SISTING STEEL AND HETEQD @151 PRODUGING SAME.

Application filed June 22, near. serial Ito. Matti not protected by acoating of oil which is now the universal custom.

To process the metal according to my invention, it may be first hotrolled and then freed of its oxidized surface by any of the well knownmethods, such as etching and sand-blasting or sudden chilling and it mayhe washed. It is then given a coating of iron phosphate. This may bedone by boiling the metal in a dilute solution of hosphoric acid (onepound of absolute acid to 100 pounds of water) or the metal may besimply dipped in a solution of phosphoric acid and Water (one pound ofacid to 20 pounds of water). The water may be hot or cold. Anothermethod of forming the phosphate coating on the surface is to apply acoating of a thermally decomposable phosphate such as ammonium oraniline phosphate and to then heat the metal to liberate phosphoric acidwhich attacks the surface forming the phosphate coating. Ur an acid saltof phosphoric acid may be applied to the surface which will havesufficient acid reaction to produce the desired coating.

Alter securing the phosphated surface, the metal is then rolled. It maybe allowed to thoroughly dry first if the Wet methods mentioned abovehave been used or the metal may be passed through the rolls in the wetcondition.

The metal resulting from this process is dull in appearance and has theadvantageous property of not readily rusting and it may he paintedwithout danger of the metal rusting under the paint as the cause forthis is neutralized in my process by the action of the free or combinedphosphoric acid.

It will be obvious art that modifications may be made in details ofprocedure and in its chemical aspects the range of equivalents is wide,hence I do not intend to limit the invention as to such matters orotherwise than as the prior art and the appendedclaims may require.

I claim:

1. The method of producing rust resisting steel consisting in treatingthe steel with phos horic acid and 't on rolling the steel.

2. The method of producing rust resisting steel-consistingin picklingthe steel, then treatin the steel with phosphoric acid, and then ro lingthe steel.

3. The method of producing rust resistto those skilled in the ing steelconsisting in. pickling the steel, washing the steel to remove thepickle then treating the steel with phosphoric acio, and then rollingthe steel.

4:. The method of producing rust resist ing steel consisting in forminga coating of iron phosphate on the surface of the steel and then rollingthe steel.

5. The method of treating steel to prevent 10 it from rusting Whichconsists in rolling into teases?

